Safety valve for use in filling of fire extinguishers

ABSTRACT

A safety valve for use in filling of fire extinguishers and the like is disclosed. There is provided the usual storage container for containing fire extinguishing chemicals under pressure and having a control head attached thereto at one end. The control head is provided with a pair of discharge passages in fluid flow communication with the interior of the container. A main valve seals one of the passages and a safety valve is provided to seal the other passage. Preferably, the two passages are continuous so that a stem of the main valve extends from the one passage into the other. The safety valve is acted upon by the fluid when the main valve is open. A compression spring is connected between the stem and the safety valve tending to close the latter when the former is open. When fluid pressure on the safety valve is greater than the pressure from the spring, the safety valve moves to vent fluid from the container to the atmosphere.

United States Patent 1191 Hansen 1 51 Jan.30, 1973 SAFETY VALVE FOR USE IN FILLING Primary Examiner-M. Henson Wood, Jr.

OF FIRE EXTINGUISHERS Assistant Examiner-Edwin D. Grant [75] Inventor: Arne Hansen,New City,N.Y. AHOrneYTDarby & Darby [73] Assignee: Walter Kidde & Company, Inc., [57] ABSTRACT B ll ll e evl A safety valve for use in filling of fire extinguishers [22] Flled? 1971 and the like is disclosed. There is provided the usual [21] Appl. No.: 197,349 storage container for containing fire extinguishing chemicals under pressure and having a control head attached thereto at one end. The control head is pro- 16981252155433 vided with a pair of discharge passages in fluid flow Field of Search-169,19 31 31 commurlncatiorli with tthehinterior of th; conftatiner.1 A 141/18 20 main va ve sea s one o t e passages an a sa e y va ve lS prov1ded to seal the other passage. Preferably, the [56] References Cited two passages are continuous so that a stem of the main valve extends from the one passage into the other. The UNITED STATES PATENTS safety valve is acted upon by the fluid whenthe main 2,120,297 6/1938 Reinecke ..l69/3l R valve Open A compresson Sprmg .comected 3,209,949 10/1965 Gurtler ..l69/31 R X between the stem and the safety valve tending to close 3,530,941 9 1970 Hansen 6m. ..l69/30 x the latter when the former is p when fluld P 3,662,836 1972 Siimes ..169/31 R sure on t saf ty valve is greater than the pressure from the spring, the safety valve moves to vent fluid FOREIGN PATENTS OR APPLICATIONS from the container to the atmosphere.

698,925 l2/l965 ltaly ..l69/3l R 6,413,666 1965 Netherlands ..169 30 12 1 D'awmg F'gure [I SI 39 I I 1 I 1 1 1 r i I 31' 22. IO N 1 l 21- I l l l 19 1 17' 1 i I llu l BACKGROUND OF THE INVENTION The present invention relates to apparatus for confining and dispensing a fluid medium under pressure, such as portable fire extinguishers and the like, and more particularly to chemical-type fire extinguishers having a relief valve or safety valve communicating with the pressurized fluid and adapted to release such fluid when the pressure reaches a predetermined value.

Portable fire extinguishers of the type referred to herein, are normally charged or filled by inserting a special tool or jig into the outlet nozzle of the apparatus. The dry fire extinguishing chemicals are then forced under pressure through the outlet and into the container of the fire extinguisher. By way of example only, the normal fill pressure is about 195 pounds per square inch.

Control over the pressurizing operation is normally exercised by a pressure regulator on the filling'apparatus. Such regulators may act in two ways. The regulator may control the pressure entering the container. Under these conditions, fluid will flow into the container so long as the pressure therein is less than the incoming pressure as determined by the regulator. When the pressures equalize, as when the container is full, there is no longer a net flow of fluid into the container. Other types of regulators may sense the pressure which is building within the fluid container of the fire extinguisher, and when a predetermined pressure is reached, the incoming or pressurizing flow from the filling apparatus is interrupted. In the absence of automatic filling apparatus, the operator will normally observe a pressure gauge which registers the internal pressure of the fire extinguisher. When the observed pressure reaches a predetermined value, the operator disconnects the filling apparatus.

It may happen, however, that the pressure regulator on the filling apparatus will malfunction, or, alternatively, the operator may not pay proper attention to the gauges. Under such circumstances, there is a likelihood that the container of the fire extinguisher will be overfilled, or overpressurized, since the storage pressure of the filling apparatus is normally extremely high relative to the operating pressure within the-fluid reservoir of the fire extinguisher. Such overpressurization may cause the container of the fire extinguisher'to burst, resulting in serious, if not fatal, injury.

Accordingly, the present invention provides a relief valve for sensing the pressure which builds up in the fire extinguisher during the filling operation. When the fluid within the container reaches a predetermined value, the valve will raise and provide a release to vent such fluid to the atmosphere. In a preferred form of the invention, the relief valve is of the poppet type slidably engaging an extension or elongated stem of the main valve which controls access to the fluid reservoir of the fire extinguisher. The poppet valve is adapted to be acted upon by the pressurized fluid in the container when the main valve is open. The main valve and the safety valve are operatively connected by a compression spring connected between the stem and the poppet and which exerts a force on the poppet tending to close the same when the main valve is open. When the force exerted on the poppet valve by the pressurized fluid is greater than the force exerted on the poppet valve by the compression spring, the poppet valve moves to vent fluid from the container to the atmosphere.

It is therefore an object of the present invention to provide apparatus fordispensing a fluid medium under pressure having a safety valve for rapidly discharging fluid from the container when the pressure exceeds a predetermined value.

. sensitive poppet-type relief valve which will move to discharge fluid from the fire extinguisher when it is overpres'surized.

Still another object is to provide a safety valve for use in filling of fire extinguishers, which will reset itself automatically when the internal pressure of fluid being exhausted from the container is reduced to a predetermined value.

BRIEF DESCRIPTION OF THE DRAWINGS For a further understanding of the present invention, reference may be had to the accompanying drawing, in whichv there is illustrated a longitudinal view taken partly in cross-section of a preferred embodiment of a fire extinguisher equipped with a safety valve in accordance with the present invention.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, there is shown, by way of example, a tire extinguisher, generally indicated by reference numeral 10, having a container or receptacle 11 for storing a fluid medium under pressure. The container 11 may be formed of a suitable metal such as stainless steel and is preferably provided with a domed end lla having an outwardly flared neck portion 12. An opening 12a is formed in the neck 12.

A control head 13 is inserted into the opening 12a in such a way as to form a fluid-tight seal with an inner surface 16 on the neck. The sealing arrangement between the neck 12 and the control head may be ac complished in several ways, however, it has been found convenient to provide on the head 13 a sealing member, such as an O-ring 14, to engage the necks inner surface 16. For this purpose, the control head 13 is provided adjacent its .lower end with an annular recess 17 to contain the O-ring.

The body of the control head 13 is preferably made of a plastic material such as polymerized formaldehyde, and is provided part way therethrough with a first axial bore 15 having an enlarged diameter lower end portion 21 for receiving a siphon tube 18. Tube 18 extends downwardly from the control head 13 into the container 11 where the chemical, for example an extinguishing agent in powder form, is stored. The upper end of the enlarged diameter portion 21 is formed with an inwardly tapered wall portion 22 to serve as a valve seat for a valve member 29 movable to control the charging and discharging of fluid from the container 11. A reduced diameter portion 23 of the bore 15 extends above the valve seat 22 and has an angled bend of substantially tobe in fluid flow communication with a substantially laterally extending discharge passageway 24. The discharge passageway is formed within a protruding nose portion 46 of the control head which may be pointed at the fire to be extinguished to direct the flow of exhausting pressurized fluid.

The control head. 13 is further provided with a stepped axial bore 26 which is coaxial with the bore 21 and extends from the upper end toward the interior of the control head. The upper portion 27 of bore 26 is of the largest diameter, and a reduced diameter portion 28 is in fluid flow communication with the curved portion 23 of bore 21.

The valve 29 has a head 31 and a stem 32 and is mounted within the control head 13 so that the head 31 is positioned and can travel within the bore 21. The stem 32 extends upwardly from the head 31 through the stepped bore 26 above the upper surface of the control head. The valve stem 32, therefore, extends along an axis common to the bores 21 and 26 and the siphon tube 18. An O-ring 33 is preferably mounted on the valve head 31 for engagement with the valve seat 22 to provide a fluid tight seal between the bore 21 and the discharge passageway 24.

A valve operating lever 43 is pivotally mounted at the top of the control head 13. Preferably, the lever 43 is mounted at pivot 44 on one side of the top portion of the control head and extends laterally across over the top or upper end of the control head and the protruding valve stem 32. In the embodiment illustrated, the lever 43 extends laterally outwardly from the control head substantially coextensively with a handle 45 which is swaged or otherwise rigidly secured to the flared neck portion 12. The lever 43 may be provided with an outwardly protruding flange 43a which extends directly over the upper end of the valve stem 32 to engage the valve stem when the lever is pivoted in a clockwise direction, as viewed in the drawing. The valve 29, accordingly, may be operated when the lever 43 and the handle 45 are grasped in one hand and squeezed together.

1n the preferred embodiment, the reduced diameter portion 28 of the bore 26 is provided with an annular recess 36 which supports an O-ring 34 in sealing relationship with the valve stem 32. The recess 36 is formed with a shoulder portion 36a upon which the O- ring 34 rests. The O-ring 34, therefore, may be moved to slide along the valve stem 32 upwardly within the stepped bore 26 toward the large diameter portion 27, as will be more fully explained below.

A valve member 37, which is preferably annular in shape, is slidably mounted on the valve stem 32 in the large diameter portion 27 of bore 26. The diameter of the valve member 37 is less than that of the enlarged diameter portion 27 of the bore 26 so that a substantially annular passageway is formed between the valve and the wall of bore portion 27. The shoulder 38 between stepped bore portions 27 and 28 serves as a seat for the valve member 37.

A collar 39, which is shown as a washer having a downwardly extending flange, is positioned near the upper end of the valve stem above the body of the control head 13. A helical coil spring 41 is positioned between the collar 39 and valve member 37. Valve member 37 is provided with a recessed portion 42 to receive the lowered end of spring 41. The collar 39 against which the upper end of the spring pushes, is held onto the stem 32 by a C-washer 50 snapped into a retaining groove 51.

Spring 41 serves simultaneously to bias the valve 29 upwardly to effect the seal between the valve head 31 and the valve seat 22, and to bias the valve '37 downwardly to effect the seal between the lower face of valve 37 and the O-ring 34.

It should be noted that since the valve members 29 and 37 act respectively in opposite directions, the force produced by the coil spring 41 serves to seat each of the valve members simultaneously. As explained previously, the tire extinguisher is of the type adapted to be partially filled with a fluid medium, such as water or dry chemical powder, and then pressurized with a gas. Fluid may thereby be forced up through the siphon tube 18 and out through the valve 29 and discharge passage 24 when the valve 29 is opened. The extinguisher is charged by injecting the liquid or dry powder chemical fire-extinguishing agent under pressure into the container 11 through the outlet 48 and discharge passageway 24. Preferably, the valve 29 is opened by depressing the valve operating lever 43. The valve is thereby moved downwardly away from the valve seat 22, and the charging fluid is permitted to enter the container 11. Alternatively, pressure applied through the incoming fluid may force the valve member 29 downwardly against the pressure of the spring 41 to open the passage to the siphon tube 18 and the container 1 1.

The safety feature of the invention operates as follows. As the container 11 is pressurized, the valve 29 is moved downward, thereby compressing the spring between the collar 39 and the valve 37 and causing energy to be stored in the spring. A predetermined force is exerted by the spring against the valve 37 effecting the seal of the reduced diameter bore portion 28 by the bottom wall seat 38 of valve 37. If the pressure within the fire extinguisher reaches a value grater than this predetermined force, the resultant of the forces acting on the O-ring 34 is directed upwardly to lift the O-ring 34 off of the shoulder 36a. The O-ring 34 is therefore caused to slide upwardly along the valve stem 32, and carries the valve member 37 upwardly against the pressure of the spring 41. Once the O-ring is moved past the upper surface of the valve seat 38, the fluid medium may escape through the annular passageway formed between the inner surface of the bore 27 and the outer surface of the valve member 37, thereby discharging the container and reducing the pressure therein. In the preferred embodiment, once the pressure within the container has declined sufficiently, downward pressure on the valve member 37 from spring 41 causes the valve to reset itself against the shelf 38 and the O-ring to reset itself within the annular recess 36.

It should be noted that the safety valve 37 may be unseated independently of the position of the main valve 29; however, the safety feature is usually significant only when the O-ring 34 is exposed to and senses the force exerted by the pressurized chemical fluid within the container 1 1. This occurs when the main valve 29 is open, as during the charging or filling operation.

It should also be noted that in the normal operation of the present fire extinguisher, downward pressure from the valve operating lever 43 causes the valve member 29 to move downwardly and unseat to open the discharge passage to the pressurized fluid medium.

The movement of stem 32 with the downward movement of the valve 29 serves to compress the spring 41, thereby increasing the pressure on the valve member 37, which pressure tends further to effect the seal. This arrangement provides additional protection against inadvertent escape through the safety valve 37 of fluid medium which is being discharged in the normal operation of the apparatus.

What is claimed is:

1. Apparatus for dispensing a fluid medium under pressure comprising:

a container for storing the fluid medium and having an opening at one end;

a control member closing said opening and having first and second discharge passages in fluid flow communication with said opening;

a first valve mounted within said first passage and movable to seal said opening;

a second valve mounted within said second passage and movable to seal said second passage, said second valve having a pressure surface communicating with the fluid medium when said first valve is open, for producing a first force in response to the pressure of the fluid tending to open said second valve; and

means operatively connecting said first and second valves for exerting a second force tending to close said second valve when said first valve is open, said second valve being adapted to open said second passage to vent fluid from said container when said first force is greater than said second force.

2. Apparatus as in claim 1, wherein said first and second passages are continuous.

3. Apparatus as in claim 2, wherein at least a portion of each of said first and second passages is substantially coaxial with the other and with said opening.

4. Apparatus as in claim 3, wherein said first valve includes an operating arm extending into said second passage.

5. Apparatus as in claim 4, wherein said second passage comprises a stepped cross-sectional configuration having a large diameter portion and a reduced diameter portion.

6. Apparatus as in claim 5, wherein said second valve comprises first and second valve members, each of said members surrounding a portion of said operating arm, said first member being disposed within said large diameter portion of said second passage and said second member being disposed within said reduced diameter portion.

7. Apparatus as in claim 6, wherein said second member comprises an O-ring to cooperate with said operating arm and the sidewalls of said reduced diameter portion of said second passage to form a seal to close said second passage.

8. Apparatus as in claim 7, wherein the diameter of said second valve member is less than the diameter of said large diameter portion of said second passage.

9. Apparatus as in claim 8, wherein said pressure surface is formed as part of the external surface of said O- ring.

10. Apparatus as in claim 9, wherein said arm extends completely through said second passage to protrude beyond the perimeter of said control member and includes an annular flange adjacent its outer end and 1prpg'ecting radially therefrom. v

1 pparatus as m claim 10, wherein said means 

1. Apparatus for dispensing a fluid medium under pressure comprising: a container for storing the fluid medium and having an opening at one end; a control member closing said opening and having first and second discharge passages in fluid flow communication with said opening; a first valve mounted within said first passage and movable to seal said opening; a second valve mounted within said second passage and movable to seal said second passage, said second valve having a pressure surface communicating with the fluid medium when said first valve is open, for producing a first force in response to the pressure of the fluid tending to open said second valve; and means operatively connecting said first and second valves for exerting a second force tending to close said second valve when said first valve is open, said second valve being adapted to open said second Passage to vent fluid from said container when said first force is greater than said second force.
 1. Apparatus for dispensing a fluid medium under pressure comprising: a container for storing the fluid medium and having an opening at one end; a control member closing said opening and having first and second discharge passages in fluid flow communication with said opening; a first valve mounted within said first passage and movable to seal said opening; a second valve mounted within said second passage and movable to seal said second passage, said second valve having a pressure surface communicating with the fluid medium when said first valve is open, for producing a first force in response to the pressure of the fluid tending to open said second valve; and means operatively connecting said first and second valves for exerting a second force tending to close said second valve when said first valve is open, said second valve being adapted to open said second Passage to vent fluid from said container when said first force is greater than said second force.
 2. Apparatus as in claim 1, wherein said first and second passages are continuous.
 3. Apparatus as in claim 2, wherein at least a portion of each of said first and second passages is substantially coaxial with the other and with said opening.
 4. Apparatus as in claim 3, wherein said first valve includes an operating arm extending into said second passage.
 5. Apparatus as in claim 4, wherein said second passage comprises a stepped cross-sectional configuration having a large diameter portion and a reduced diameter portion.
 6. Apparatus as in claim 5, wherein said second valve comprises first and second valve members, each of said members surrounding a portion of said operating arm, said first member being disposed within said large diameter portion of said second passage and said second member being disposed within said reduced diameter portion.
 7. Apparatus as in claim 6, wherein said second member comprises an O-ring to cooperate with said operating arm and the sidewalls of said reduced diameter portion of said second passage to form a seal to close said second passage.
 8. Apparatus as in claim 7, wherein the diameter of said second valve member is less than the diameter of said large diameter portion of said second passage.
 9. Apparatus as in claim 8, wherein said pressure surface is formed as part of the external surface of said O-ring.
 10. Apparatus as in claim 9, wherein said arm extends completely through said second passage to protrude beyond the perimeter of said control member and includes an annular flange adjacent its outer end and projecting radially therefrom.
 11. Apparatus as in claim 10, wherein said means operatively connecting said first and second valves comprises a compression spring disposed between the undersurface of said flange and the upper surface of said second valve. 